Power converter, display device including power converter, system including display device, and method of driving display device

ABSTRACT

A power converter includes a voltage conversion unit that provides a first driving voltage at a first output electrode by converting a power supply voltage in response to a first control signal, the voltage conversion unit being configured to provide a second driving voltage at a second output electrode by converting the power supply voltage after a short detection period, the voltage conversion unit being configured to shut down in response to a third control signal, and a short detection unit that generates the third control signal by comparing a magnitude of a voltage of the second output electrode with a magnitude of a reference voltage during the short detection period.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation application based on pending application Ser. No.13/137,114, filed Jul. 21, 2011, the entire contents of which is herebyincorporated by reference.

BACKGROUND

1. Field

Embodiments relate to a power converter, a display device including apower converter, a system including a display device, and a method ofdriving display device.

2. Description of the Related Art

Generally, a display device includes a display panel having a pluralityof pixels arranged in a matrix form. Each of the plurality of pixelsoperates in response to a driving voltage.

For example, each of the plurality of pixels included in an organiclight emitting display may have an organic light emitting diode (OLED).The OLED generates light by coupling holes, which are provided from ananode to which a positive driving voltage (ELVDD) is applied, andelectrons, which are provided from a cathode to which a negative drivingvoltage (ELVSS) is applied, in an organic material layer formed betweenthe anode and the cathode.

SUMMARY

An embodiment is directed to a power converter, including a voltageconversion unit that provides a first driving voltage at a first outputelectrode by converting a power supply voltage in response to a firstcontrol signal, the voltage conversion unit being configured to providea second driving voltage at a second output electrode by converting thepower supply voltage after a short detection period, the voltageconversion unit being configured to shut down in response to a thirdcontrol signal, and a short detection unit that generates the thirdcontrol signal by comparing a magnitude of a voltage of the secondoutput electrode with a magnitude of a reference voltage during theshort detection period.

The voltage conversion unit may include a control unit that enables afirst driving signal and that enables a second control signal during theshort detection period when the first control signal is enabled, thecontrol unit being configured to enable a second driving signal and todisable the second control signal after the short detection period, thecontrol unit being configured to provide the second control signal tothe short detection unit, the control unit being configured to disablethe first driving signal and the second driving signal when the thirdcontrol signal is enabled, a first voltage converter that generates thefirst driving voltage by converting the power supply voltage while thefirst driving signal is enabled, and a second voltage converter thatgenerates the second driving voltage by converting the power supplyvoltage while the second driving signal is enabled.

The control unit may include a timing generator that controls a lengthof the short detection period.

The voltage conversion unit may further include a comparator thatprovides an enabled fourth control signal to the timing generator when amagnitude of the first driving voltage is equal to or larger than amagnitude of a target voltage, and the timing generator may control thelength of the short detection period based on a length of a time periodfrom a time when the first control signal is enabled to a time when thefourth control signal is enabled.

The short detection unit may sense the magnitude of the voltage of thesecond output electrode at a time during the short detection period andcompare the sensed magnitude of the voltage of the second outputelectrode with the magnitude of the reference voltage to generate thethird control signal.

The short detection unit may include a comparator that enables the thirdcontrol signal when the magnitude of the voltage of the second outputelectrode is equal to or larger than the magnitude of the referencevoltage and that disables the third control signal when the magnitude ofthe voltage of the second output electrode is smaller than the magnitudeof the reference voltage, and a first switch connected between the powersupply voltage and the comparator and configured to selectively providethe power supply voltage to the comparator in response to a secondcontrol signal, the second control signal being configured to be enabledduring the short detection period and configured to be disabled afterthe short detection period.

The first switch may be turned on to provide the power supply voltage tothe comparator when the second control signal is enabled, and may beturned off to stop providing the power supply voltage to the comparatorwhen the second control signal is disabled.

The short detection unit may further includes a pull-down unit connectedbetween the second output electrode and a ground voltage, the pull-downunit being configured to be turned on in response to the second controlsignal.

The pull-down unit may include a pull-down register, a first terminal ofthe pull-down register being connected to the second output electrode,and a second switch connected between a second terminal of the pull-downregister and the ground voltage, the second switch being configured tobe turned on when the second control signal is enabled, and to be turnedoff when the second control signal is disabled.

The second switch may include NMOS transistor, the NMOS transistorhaving a drain connected to the second terminal of the pull-downregister, a source connected to the ground voltage and a gate receivingthe second control signal.

The short detection unit may further include an inverter that generatesan inverted control signal by inverting the second control signal, and asecond switch connected between an output electrode of the comparatorand the ground voltage, the second switch being configured to be turnedon in response to the inverted control signal.

The second switch may be turned off to separate the output electrode ofthe comparator from the ground voltage when the inverted control signalis disabled, and may be turned on to disable the third control signalwhen the inverted control signal is enabled.

The short detection unit may further include a reference voltagegenerator that generates the reference voltage.

The first driving voltage may have a positive potential and the seconddriving voltage may have a negative potential.

The first driving voltage may have a negative potential and the seconddriving voltage may have a positive potential.

Another embodiment is directed to a display device, including a displaypanel including a plurality of pixels, the plurality of pixels beingconfigured to operate in response to a first driving voltage, a seconddriving voltage, and a data signal, a power converter that provides thefirst driving voltage at a first output electrode of the power converterand that provides the second driving voltage at a second outputelectrode of the power converter at a time interval of a short detectionperiod in response to a first control signal, the power converter beingconfigured to shut down when a magnitude of a voltage of the secondoutput electrode is equal to or larger than a magnitude of a referencevoltage during the short detection period, and a driving unit thatprovides the data signal to the display panel and that provides thefirst control signal to the power converter.

The first driving voltage may have a positive potential and the seconddriving voltage may have a negative potential.

The first driving voltage may have a negative potential and the seconddriving voltage may have a positive potential.

The short detection period may correspond to N frame cycles, where N isa positive integer.

The power converter may connect the second output electrode to a groundvoltage through a pull-down register during the short detection period.

The driving unit may provide a data signal corresponding to black colorto the display panel during the short detection period.

The driving unit may provide the data signal corresponding to blackcolor to the display panel for at least one frame cycle from the end ofthe short detection period.

The power converter may include a voltage conversion unit that providesthe first driving voltage at the first output electrode by converting apower supply voltage in response to the first control signal, thevoltage conversion unit being configured to provide the second drivingvoltage at the second output electrode by converting the power supplyvoltage after the short detection period, the voltage conversion unitbeing configured to shut down in response to a third control signal, anda short detection unit that generates the third control signal bycomparing a magnitude of a voltage of the second output electrode with amagnitude of the reference voltage during the short detection period.

Each of the plurality of pixels may include an organic fight emittingdiode.

Another embodiment is directed to a method of driving a display device,the method including providing a first driving voltage from a firstoutput electrode of a power converter to a display panel, comparing amagnitude of a voltage of a second output electrode of the powerconverter with a magnitude of a reference voltage during a shortdetection period, providing a second driving voltage from the secondoutput electrode of the power converter to the display panel after theshort detection period when the magnitude of the voltage of the secondoutput electrode is kept smaller than the magnitude of the referencevoltage daring the short detection period, and shutting down the powerconverter when the magnitude of the voltage of the second outputelectrode is equal to or larger than the magnitude of the referencevoltage during the short detection period.

The first driving voltage may have a positive potential and the seconddriving voltage may have a negative potential.

The first driving voltage may have a negative potential and the seconddriving voltage may have a positive potential.

The method may further include connecting the second output electrode ofthe power converter to a ground voltage through a pull-down registerduring the short detection period.

The method may further include providing a data signal corresponding toblack color to the display panel before providing the first drivingvoltage to the display panel.

Providing the data signal may include providing the data signalcorresponding to black color to the display panel during the shortdetection period and for at least one frame cycle from the end of theshort detection period.

The display panel may include an organic light emitting diode.

Another embodiment is directed to a system, including a storage devicethat stores image data, a display device that displays the image data,and a processor that controls the storage device and the display device.The display device may include a display panel including a plurality ofpixels, the plurality of pixels being configured to operate in responseto a first driving voltage, a second driving voltage, and a data signal,a power converter that provides the first driving voltage at a firstoutput electrode of the power converter and that provides the seconddriving voltage at a second output electrode of the power converter at atime interval of a short detection period in response to a first controlsignal, the power converter being configured to shut down when amagnitude of a voltage of the second output electrode is equal to orlarger than a magnitude of a reference voltage during the shortdetection period, and a driving unit that provides the data signal tothe display panel and that provides the first control signal to thepower converter.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages will become more apparent tothose of skill in the art by describing in detail example embodimentswith reference to the attached drawings, in which:

FIG. 1 illustrates a block diagram of a power converter according toexample embodiments.

FIG. 2 illustrates a flow chart of an example of a method of driving apower converter of FIG. 1 according to an example embodiment.

FIGS. 3, 4, 5, 6 and 7 illustrate block diagrams of examples of a powerconverter of FIG. 1.

FIGS. 8, 9, 10 and 11 illustrate timing diagrams for describing anoperation of the power converter of FIG. 1.

FIG. 12 illustrates a block diagram of a display device including apower converter according to example embodiments.

FIG. 13 illustrates a block diagram of an example of a display device ofFIG. 12.

FIG. 14 illustrates a circuit diagram of an example of a pixel includedin a display panel of a display device of FIG. 13.

FIGS. 15, 16 and 17 illustrate flow charts of examples of methods ofdriving a display device of FIG. 12.

FIGS. 18, 19, 20 and 21 illustrate timing diagrams for describing anoperation of the display device of FIG. 13.

FIG. 22 illustrates a block diagram of a system including a displaydevice according to example embodiments.

DETAILED DESCRIPTION

Korean Patent Application No. 10-2010-0116832, filed on Nov. 23, 2010,in the Korean Intellectual Property Office, and entitled: “DC-DCConverter, Display Device Including DC-DC Converter, System IncludingDisplay Device and Method of Driving Display Device,” and Korean PatentApplication No. 10-2011-0046580, filed on May 18, 2011, in the KoreanIntellectual Property Office, and entitled: “Power Converter, DisplayDevice including Power Converter, System Including Display Device andMethod of Driving Display Device,” are incorporated by reference hereinin its entirety

Example embodiments will now be described more full hereinafter withreference to the accompanying drawings; however, they may be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

In the drawing figures, the dimensions of layers and regions may beexaggerated for clarity of illustration. It will also be understood thaten a layer or element is referred to as being “on” another layer orsubstrate, it can be directly on the other layer or substrate, orintervening layers may also be present. Further, it will be understoodthat when a layer is referred to as being “under” another layer, it canbe directly under, and one or more intervening layers may also bepresent. In addition, it will also be understood that when a layer isreferred to as being “between” two layers, it can be the only layerbetween the two layers, or one or more intervening layers may also bepresent. Like reference numerals refer to like elements throughout.

It will be understood that, although the terms first, second, etc., maybe used herein to describe various elements, these elements should notbe limited by these terms. Rather, these terms are merely used to aidein distinguishing one element from another. For example, a first elementcould be termed a second element, and, similarly, a second element couldbe termed a first element. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises,” “comprising,”“includes” and/or “including,” when used herein, specify the presence ofstated features, integers, steps, operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps, operations, elements, components,and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof skill in the art to which this inventive concept belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 illustrates a block diagram of a power converter 10 according toexample embodiments.

In the example embodiment shown in FIG. 1, the power converter 10includes a voltage conversion unit 100 and a short detection unit 200.

The voltage conversion unit 100 may provide a first driving voltage DV1at a first output electrode 110 by converting to power supply voltageVDD, and may enable a second control signal CON2 during a shortdetection period in response to a first control signal CON1 receivedfrom an external device. The voltage conversion unit 100 may disable thesecond control signal CON2 and provide a second driving voltage DV2 at asecond output electrode 120 by converting the power supply voltage VDDafter the short detection period. The voltage conversion unit 100 mayshut down in response to a third control signal CON3. For example, thevoltage conversion unit 100 may stop generating the first drivingvoltage DV1 and the second driving voltage DV2 in response to the thirdcontrol signal CON3.

The short detection unit 200 may generate the third control signal CON3by comparing a magnitude of a voltage of the second output electrode 120with a magnitude of a reference voltage Vref during the short detectionperiod. The short detection unit 200 may stop operating after the shortdetection period. For example, the short detection unit 200 may operatewhen the second control signal CON2 is enabled and stop operating whenthe second control signal CON2 is disabled.

In some example embodiments, the short detection unit 200 may sense themagnitude of the voltage of the second output electrode 120 at a timeduring the short detection period and compare the sensed magnitude ofthe voltage of the second output electrode 120 with the magnitude of thereference voltage Vref to generate the third control signal CON3.

The first control signal CON1, the second control signal CON2, and thethird control signal CON3 may be enabled at a logic high level and bedisabled at a logic low level.

FIG. 2 illustrates a flow chart of an example of a method of driving apower converter of FIG. 1 according to an example embodiment.

In the example embodiment shown in FIG. 2, the voltage conversion unit100 may provide the first driving voltage DV1 at the first outputelectrode 110 by converting the power supply voltage VDD and may enablethe second control signal CON2 during the short detection period inresponse to the first control signal CON1 (operation S10 in FIG. 2).

The short detection unit 200 may generate the third control signal CON3by comparing the magnitude of the voltage of the second output electrode20 with the magnitude of the reference voltage Vref during the shortdetection period, and may provide the third control signal CON3 to thevoltage conversion unit 100 (operation S20). The voltage conversion unit100 may determine whether the third control signal CON3 is enabledduring the short detection period (operation S30 in FIG. 2).

With reference to the state of the third control signal CON3 inoperation S30, if the third control signal CON3 is kept disabled duringthe short detection period, the voltage conversion unit 100 may disablethe second control signal CON2 and provide the second driving voltageDV2 at the second output electrode 120 by converting the power supplyvoltage VDD after the short detection period, so that the voltageconversion unit 100 may perform a normal operation after the shortdetection period (operation S40 in FIG. 2).

With further reference to the state of the third control signal CON3 inoperation S30, if the third control signal CON3 is enabled during theshort detection period, the voltage conversion unit 100 may shut down tostop generating the first driving voltage DV1 and the second drivingvoltage DV2 (operation S50 in FIG. 2).

As described above, the power converter 10 may provide the first drivingvoltage DV1 at the first output electrode 110 and the second drivingvoltage DV2 the second output electrode 120 at a time interval of theshort detection period. The power converter 10 may determine whether themagnitude of the voltage of the second output electrode 120 increasesaccording to an increase of the magnitude of the first driving voltageDV1 during the short detection period. If the magnitude of the voltageof the second output electrode 120 increases over the magnitude of thereference voltage Vref during the short detection period, the powerconverter 10 may determine that a wiring connected to the first outputelectrode 110 and a wiring connected to the second output electrode 120are shorted with each other and stop generating the first drivingvoltage DV1 and the second driving voltage DV2.

FIG. 3 illustrates a block diagram of an example of the power converter10 of FIG. 1.

In the example embodiment shown in FIG. 3, a power converter 10 aincludes a voltage conversion unit 100 a and a short detection unit 200a.

The voltage conversion unit 100 a may include a control unit 130, afirst voltage converter 140, and a second voltage converter 150.

The control unit 130 may enable a first driving signal DRV1 and enablethe second control signal CON2 during the short detection period whenthe first control signal CON1 is enabled. The control unit 130 mayenable a second driving signal DRV2 and disable the second controlsignal CON2 after the short detection period. The control unit 130 maydisable the first driving signal DRV1 and the second driving signal DRV2when the third control signal CON3 is enabled during the short detectionperiod.

The first voltage converter 140 may generate the first driving voltageDV1 by converting the power supply voltage VDD while the first drivingsignal DRV1 is enabled, and output the first driving voltage DV1 throughthe first output electrode 110.

The second voltage converter 150 may generate the second driving voltageDV2 by converting the power supply voltage VDD while the second drivingsignal DRV2 is enabled, and output the second driving voltage DV2through the second output electrode 120.

The first voltage converter 140 and the second voltage converter 150 maybe embodied in various forms.

The short detection unit 200 a may include a comparator 210 and a firstswitch 220.

The comparator 210 may be provided with the power supply voltage VDD tooperate. The comparator 210 may enable the third control signal CON3when the magnitude of the voltage of the second output electrode 120 isequal to or larger than the magnitude of the reference voltage Vref. Thecomparator 210 may disable the third control signal CON3 when themagnitude of the voltage of the second output electrode 120 is smallerthan the magnitude of the reference voltage Vref.

The first switch 220 may be connected between the power supply voltageVDD and the comparator 210. The first switch 220 may selectively providethe power supply voltage VDD to the comparator 210 by being turned on orbeing turned off in response to the second control signal CON2. Forexample, the first switch 220 may be turned on to provide the powersupply voltage VDD to the comparator 210 when the second control signalCON2 is enabled, and be turned off to stop providing the power supplyvoltage VDD to the comparator 210 when the second control signal CON2 isdisabled. Therefore, the short detection unit 200 a may operate onlywhen the second control signal CON2 is enabled, to provide the thirdcontrol signal CON3 (which is enabled or disabled based on a comparisonresult of the magnitude of the voltage of the second output electrode120 and the magnitude of the reference voltage Vref) to the voltageconversion unit 100 a.

The control unit 130 may include a timing generator 131 that controls alength of the short detection period. For example, if the wiringconnected to the first output electrode 110 and the wiring connected tothe second output electrode 120 are shorted with each other, themagnitude of the voltage of the second output electrode 120 increasesaccording to an increase of the magnitude of the first driving voltageDV1. Therefore, as the length of the short detection period increases,the power converter 10 a may be able to detect a more minute, shortbetween the wiring connected to the first output electrode 110 and thewiring, connected to the second output electrode 120, and thus stopgenerating the first driving voltage DV1 and the second driving voltageDV2.

FIG. 4 illustrates a block diagram of an example of the power converter10 of FIG. 1.

In the example embodiment shown in FIG. 4, a power converter 10Lincludes a voltage conversion unit 100 a and a short detection unit 200b.

The power converter 10 b of FIG. 4 has the same structure as the powerconverter 10 a of FIG. 3, except that the short detection unit 200 b ofthe power converter 10 b further includes a pull-down unit 230. Thus,duplicated descriptions will be omitted.

Relative to the short detection unit 200 a included in the powerconverter 10 a of FIG. 3, the short detection unit 20013 may furtherinclude the pull-down unit 230. The pull-down unit 230 may be connectedbetween the second output electrode 120 and a ground voltage GND. Thepull-down unit 230 may be turned on in response to the second controlsignal CON2.

The pull-down unit 230 may include a pull-down resistor 231 and a secondswitch 233. A first terminal of the pull-down resistor 231 may beconnected to the second output electrode 120. The second switch 233 maybe connected between a second terminal of the pull-down resistor 231 andthe ground voltage GND. The second switch 233 may be turned on when thesecond control signal CON2 is enabled, and may be turned off when thesecond control signal CON2 is disabled. For example, the second switch233 may include an n-type metal oxide NMOS) transistor that has a drainconnected to the second terminal of the pull-down resistor 231, a sourceconnected to the ground voltage GND, and a gate receiving the secondcontrol signal CON2.

In the power converter 10 a of FIG. 3, the second output electrode 120may be floated during the short detection period since the voltageconversion unit 100 a outputs the first driving voltage DV1 at the firstoutput electrode 110 and does not output the second driving voltage DV2at the second output electrode 120 during the short detection period.However, in the power converter 10 b of FIG. 4, since the pull-down unit230 connects the second output electrode 120 to the ground voltage GNDthrough the pull-down resistor 231 during the short detection period,the power converter 10 b may more effectively determine whether themagnitude of the voltage of the second output electrode 120 increasesaccording to the increase of the magnitude of the first driving voltageDV1 during the short detection period.

The second switch 233 may be turned off to separate the second outputelectrode 120 from the ground voltage GND after the short detectionperiod since the voltage conversion unit 100 a may perform a normaloperation (i.e., in which the voltage conversion unit 100 asimultaneously generates the first driving voltage DV1 at the firstoutput electrode 110 and the second driving voltage DV2 at the secondoutput electrode 120) after the short detection period.

In some example embodiments, the pull-down resistor 231 may be adischarge resistor that is used for discharging a capacitor (notillustrated) connected between the first output electrode 110 and theground voltage GND or a capacitor (not illustrated connected between thesecond output electrode 120 and the ground voltage GND when the voltageconversion unit 100 a is shut down. In this case, the pull-down unit 230may be embodied without a separate resistor.

FIG. 5 illustrates a block diagram of an example of the power converter10 of FIG. 1.

In the example embodiment shown in FIG. 5, a power converter 10 cincludes a voltage conversion unit 100 a and a short detection unit 200c.

The power converter 10 c of FIG. 5 has the same structure as the powerconverter 10 b of FIG. 4, except that the short detection unit 200 c ofthe power converter 10 c further includes an inverter 240 and a thirdswitch 250. Thus, duplicated descriptions will be omitted.

Relative to the short detection unit 200 b included in the powerconverter 10 b of FIG. 4, the short detection unit 200 e may furtherinclude the inverter 240 and the third switch 250.

The inverter 240 may generate an inverted control signal by invertingthe second control signal CON2.

The third switch 250 may be connected between an output electrode of thecomparator 210 and the ground voltage GND. The third switch 250 may beturned on in response to the inverted control signal. For example, thethird switch 250 may be turned off to separate the output electrode ofthe comparator 210 from the ground voltage GND when the inverted controlsignal is disabled, and may be turned on to disable the third controlsignal CON3 when the inverted control signal is enabled. That is, thethird switch 250 may be turned off during the short detection period tolet the third control signal CON3 outputted from the comparator 210 tobe provided to the voltage conversion unit 100 a, and be turned on afterthe short detection period to disable the third control signal CON3.

In the power converter 10 a of FIG. 3 and the power converter 10 b ofFIG. 4 the output electrode of the comparator 210 may be floated afterthe short detection period since the first switch 220 is turned off tostop providing the power supply voltage VDD to the comparator 210 afterthe short detection period. However, in the power converter 10 c of FIG.5, since the inverter 240 and the third switch 250 connects the outputelectrode of the comparator 210 to the ground voltage GND to keep thethird control signal CON3 disabled after the short detection period, thepower converter 10 c may be prevented from shutting down by the thirdcontrol signal CON3 having a logic high level after the short detectionperiod.

FIG. 6 illustrates a block diagram of an example of the power converter10 of FIG. 1.

In the example embodiment shown in FIG. 6, a power converter 10 dincludes a voltage conversion unit 100 a and a short detection unit 200c 1.

The power converter 10 d of FIG. 6 has the same structure as the powerconverter 10 c of FIG. 5, except that the short detection unit 200 d ofthe power converter 10 d further includes a reference voltage generatorREFGEN 260. Thus, duplicated descriptions will be omitted.

Relative to the short detection unit 200 c included in the powerconverter 10 c of FIG. 5, the short detection unit 200 d may furtherinclude the reference voltage generator 260.

The reference voltage generator 260 may generate the reference voltageVref and provide the reference voltage Vref to the comparator 210.

While the power converter 10 a of FIG. 3, the power converter 10 h ofFIG. 4, and the power converter 10 c of FIG. 5 receive the referencevoltage Vref from outside, the power converter 10 d of FIG. 6 maygenerate the reference voltage Vref for itself. If the wiring connectedto the first output electrode 110 and the wiring connected to the secondoutput electrode 120 are minutely shorted with each other, the magnitudeof the voltage of the second output electrode 120 may increaserelatively slowly according to the increase of the magnitude of thefirst driving voltage DV1. Therefore, as the magnitude of the referencevoltage Vref decreases, the power converter 10 d may be able to detect amore minute short between the wiring connected to the first outputelectrode 110 and the wiring connected to the second output electrode120 to stop generating the first driving voltage DV1 and the seconddriving voltage DV2.

FIG. 7 illustrates a block diagram of an example of the power converter10 of FIG. 1.

In the example embodiment shown in FIG. 7, a power converter 10 eincludes a voltage conversion unit 100 b and a short detection unit 200a.

The power converter 10 e of FIG. 7 has the same structure as the powerconverter 10 a of FIG. 3, except that the voltage conversion unit 100 bof the power converter 10 e further includes a comparator 160. Thus,duplicated descriptions will be omitted.

Relative to the vane conversion unit 100 a included in the powerconverter 10 a of FIG. 3, the voltage conversion unit 100 h may furtherinclude the comparator 160. The comparator 160 may provide a disabledfourth control signal CON4 to the timing generator 131 when a magnitudeof the first driving voltage DV1 is smaller than a magnitude of a targetvoltage Vt and provide an enabled fourth control signal CON4 to thetiming generator 131 when the magnitude of the first driving voltage DV1is equal to or larger than the magnitude of the target voltage Vt. Thetiming generator 131 may control the length of the short detectionperiod based on a length of a time period from a time when the firstcontrol signal CON1 is enabled to a time when the fourth control signalCON4 is enabled.

The magnitude of the target voltage Vt may be predetermined as a targetmagnitude of the first driving voltage DV1 when the first drivingvoltage DV1 is completely boosted. In this case, the length of the timeperiod from the time when the first control signal CON1 is enabled tothe time when the fourth control signal CON4 is enabled may be aboosting time, which is a time period needed to boost the first drivingvoltage DV1 to the target voltage Vt. The timing generator 131 mayincrease the length of the short detection period when the boosting timeis relatively long and decrease the length of the short detection periodwhen the boosting time is relatively short. Therefore, the voltageconversion unit 100 b may sense the boosting time and optimize thelength of the short detection period based on the sensed boosting timeso that the power converter 10 e may generate the second driving voltageDV2 in an optimized time after the first control signal CON1 is enabled.

In some example embodiments, the first driving voltage DV1 may have apositive potential and the second driving voltage DV2 may have anegative potential. In this case, the voltage of the second outputelectrode 120 may increase positively according to a positive increaseof the first driving voltage DV1 when the wiring connected to the firstoutput electrode 110 and the wiring connected to the second outputelectrode 120 are shorted with each other. Therefore, the referencevoltage Vref may have a positive potential.

In other example embodiments, the first driving voltage DV1 may have anegative potential and the second driving voltage DV2 may have apositive potential. In this case, the voltage of the second outputelectrode 120 may decrease according to a decrease of the first drivingvoltage DV1 when the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are shortedwith each other. Therefore, the reference voltage Vref may have anegative potential.

In still other example embodiments, both the first driving voltage DV1and the second driving voltage DV2 may have a positive potential, orboth the first driving voltage DV1 and the second driving voltage DV2may have a negative potential.

FIGS. 8, 9, 10 and 11 illustrate timing diagrams for describing anoperation of the power converter of FIG.

FIG. 8 represents a timing diagram when the first driving voltage DV1has a positive potential, the second driving voltage DV2 has a negativepotential, and the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are notshorted with each other.

Referring to FIG. 8, the voltage conversion unit 100 provides the firstdriving voltage DV1 at the first output electrode 110 and enables thesecond control signal CON2 during the short detection period (“Tsd” inthe timing diagram) when the first control signal CON1 received from theexternal device is enabled. Since the wiring connected to the firstoutput electrode 110 and the wiring connected to the second outputelectrode 120 are not shorted with each other, the voltage DV2 of thesecond output electrode 120 does not increase according to an increaseof the first driving voltage DV1 and is kept at the ground voltage GND,which is smaller than the magnitude of the reference voltage Vref,during the short detection period Tsd. Therefore, the short detectionunit 200 disables the third control signal CON3 during the shortdetection period Tsd. The voltage conversion unit 100 disables thesecond control signal CON2 and provides the second driving voltage DV2at the second output electrode 120 by converting the power supplyvoltage VDD after the short detection period Tsd, so that the voltageconversion unit 100 performs a normal operation after the shortdetection period Tsd.

FIG. 9 represents a timing diagram when the first driving voltage DV1has a positive potential, the second driving voltage DV2 has a negativepotential, and the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are shortedwith each other.

Referring to FIG. 9, the voltage conversion unit 100 provides the firstdriving voltage DV1 at the first output electrode 110 and enables thesecond control signal CON2 during the short detection period Tsd whenthe first control signal CON1 received from the external device isenabled. Since the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are shortedwith each other, the voltage DV2 of the second output electrode 120increases according to the increase of the first driving voltage DV1during the short detection period Tsd. When the magnitude of the voltageDV2 of the second output electrode 120 increases over the magnitude ofthe reference voltage Vref during the short detection period Tsd, theshort detection unit 200 enables the third control signal CON3. Asillustrated in FIG. 9, when the third control signal CON3 is enabled,the voltage conversion unit 100 stops generating the first drivingvoltage DV1 and a magnitude of the first driving voltage DV1 decreasesto the ground voltage GND. According to the decrease of the firstdriving voltage DV1, the voltage DV2 of the second output electrode 120also decreases to the ground voltage GND, so that the power converter 10shuts down.

FIG. 10 represents a timing diagram when the first driving voltage DV1has a negative potential, the second driving voltage DV2 has a positivepotential, and the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are notshorted with each other.

Referring to FIG. 10, the voltage conversion unit 100 provides the firstdriving voltage DV1 at the first output electrode 110 and enables thesecond control signal CON2 during the short detection period Tsd whenthe first control signal CON1 received from the external device isenabled. Since the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are notshorted with each other, the voltage DV2 of the second output electrode120 does not decrease according to a decrease of the first drivingvoltage DV1 and is kept at the ground voltage GND, which is smaller thanthe magnitude of the reference voltage Vref, during the short detectionperiod Tsd. Therefore, the short detection unit 200 disables the thirdcontrol signal CON3 during, the short detection period Tsd. The voltageconversion unit 100 disables the second control signal CON2 and providesthe second driving voltage DV2 at the second output electrode 120 byconverting the power supply voltage VDD after the short detection periodTsd, so that the voltage conversion unit 100 performs a normal operationafter the short detection period Tsd.

FIG. 11 represents a timing diagram when the first driving voltage DV1has a negative potential, the second driving voltage DV2 has a positivepotential, and the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are shortedwith each other.

Referring to FIG. 11, the voltage conversion unit 100 provides the firstdriving voltage DV1 at the first output electrode 110 and enables thesecond control signal CON2 during the short detection period Tsd whenthe first control signal CON1 received from the external device isenabled. Since the wiring connected to the first output electrode 110and the wiring connected to the second output electrode 120 are shortedwith each other, the voltage DV2 of the second output electrode 120decreases according to the decrease of the first driving voltage DV1during the short detection period Tsd. When the magnitude of the voltageDV2 of the second output electrode 120 increases over the magnitude ofthe reference voltage Vref during the short detection period Tsd, theshort detection unit 200 enables the third control signal CON3. Asillustrated in FIG. 11, when the third control signal CON3 is enabled,the voltage conversion unit 100 stops generating the first drivingvoltage DV1 and a magnitude of the first driving voltage DV1 decreasesto the ground voltage GND. According to the decrease of the magnitude ofthe first driving voltage DV1, the magnitude of the voltage DV2 of thesecond output electrode 120 also decreases to the ground voltage GND, sothat the power converter to shuts down.

By way of comparison to the example embodiments described above, ageneral power converter design may sense a current flowing through anoutput electrode of the power converter and shut down only when anovercurrent, which is larger than a threshold current, flows through theoutput electrode due to a short occurring between output electrodes. Insuch a case, however, if the short between the output electrodes wereminute, such that a current flowing through the output electrode weresmaller than the threshold current, then such a power converter designmay not be effective to detect the minute short. Furthermore, if a powerconverter were to fail to detect the minute short and continue tooperate even though the minute short occurred, an overheating problemand/or a fire could result. In contrast, the example embodimentsdescribed above may circumvent such a situation.

For example, the power converter 10 may supply the first driving voltageDV1 at the first output electrode 110 and the second driving voltage DV2at the second output electrode 120 at a time interval of the shortdetection period. The power converter 10 may determine whether themagnitude of the voltage of the second output electrode 120 increasesaccording to an increase of the magnitude of the first driving voltageDV1 during the short detection period. If the magnitude of the voltageof the second output electrode 120 increases over the magnitude of thereference voltage Vref during the short detection period, the powerconverter 10 may determine that the wiring connected to the first outputelectrode 110 and the wiring connected to the second output electrode120 are shorted with each other and stop generating the first drivingvoltage DV1 and the second driving voltage DV2. Therefore, the powerconverter 10 may detect a minute short between the wiring connected tothe first output electrode 110 and the wiring connected to the secondoutput electrode 120 effectively.

FIG. 12 illustrates a block diagram of a display device including apower converter according to example embodiments.

In the example embodiment shown in FIG. 12, a display device 1000includes a display panel 300, the power converter 10, and a driving unit400.

The display panel 300 may include a plurality of pixels, each pixeloperating in response to a first driving voltage DV1, a second drivingvoltage DV2, and a data signal DATA.

The power converter 10 may provide the first driving voltage DV1 at afirst output electrode of the power converter 10 and the second drivingvoltage DV2 at a second output electrode of the power converter 10 at atime interval of a short detection period in response to a first controlsignal CON1. The power converter 10 may shut down to stop generating thefirst driving voltage DV1 and the second driving voltage DV2 when amagnitude of a voltage of the second output electrode is equal to orlarger than a magnitude of a reference voltage during the shortdetection period.

The power converter 10 included in the display device 1000 of FIG. 12may have the same structure as the power converter 10 of FIG. 1. Astructure and an operation of the power converter 10 of FIG. 1 aredescribed above with reference to FIGS. 1 to 11. Thus, details of thepower converter 10 included in the display device 1000 will not berepeated.

The driving unit 400 may provide the data signal DATA to the displaypanel 300 and may provide the first control signal CON1 to the powerconverter 10.

The display device 1000 may be implemented using various kinds of adisplay panel in so far as the display panel 300 displays an image usingat least two driving voltages DV1 and DV2 received from the powerconverter 10. For example, the display device 1000 may include anorganic light emitting display device. In this case, each of theplurality of pixels included in the display panel 300 includes anorganic light emitting diode (OLED).

Hereinafter, an organic light emitting display device including thepower converter according to example embodiments will be described.

FIG. 13 illustrates a block diagram of an example of a display device ofFIG. 12.

A display device 1000 of FIG. 13 is an organic light emitting displaydevice.

In the example embodiment shown in FIG. 13, the display device 1000includes a display panel 300, the power converter 10, and a driving unit400.

The display panel 300 may include a plurality of pixels PX arranged in amatrix form. The plurality of pixels PX may be connected to a pluralityof gate lines G1, G2, . . . , Gp and to a plurality of data lines D1,D2, . . . , Dq, where p and q represent positive integers. Each of theplurality of pixels PX may operate in response to a positive drivingvoltage ELVDD, a negative driving voltage ELVSS, gate signal and a datasignal DATA.

The driving unit 400 may include a gate driver 410, a data driver 420,and a timing controller 430.

The timing, controller 430 may receive RGB image signal R, G and B, avertical synchronization signal Vsync, a horizontal synchronizationsignal lisp main clock signal CLK, and a data enable signal DE from anexternal graphic controller (not illustrated), and may generate anoutput image signal DAT, a data control signal DCS, a gate controlsignal GCS, and a first control signal EL_ON. The timing controller 430may provide the gate control signal GCS to the gate driver 410, providethe output image signal DAT and the data control signal DCS to the datadriver 420, and provide the first control signal EL_ON to the powerconverter 10. For example, the gate control signal GCS may include avertical synchronization start signal, which controls a start ofoutputting the gate signal, a gate clock signal, which controls anoutput timing of the gate signal, and an output enable signal, whichcontrols a duration of the gate signal. The data control signal DCS mayinclude a horizontal synchronization start signal, which controls astart of outputting the data signal DATA, a data clock signal, whichcontrols an output timing of the data signal DATA and a load signal.

The gate driver 410 may consecutively apply the gate signal to the gatelines G1, G2, . . . , Gp in response to the gate control signal GCS.

The data driver 420 may apply the data signal DATA to the data lines D1,D2, . . . , Dq in response to the data control signal DCS and the outputimage signal DAT.

The power converter 10 may provide the positive driving voltage ELVDDand the negative driving voltage ELVSS to the display panel 300 inresponse to the first control signal EL_ON received from the timingcontroller 430. The power converter 10 may output selected one of thedriving voltages ELVDD and ELVSS at a first output electrode of thepower converter 10, and output the other one of the driving voltagesELVDD and ELVSS at a second output electrode of the power converter 10consecutively at a time interval of the short detection period. Thepower converter 10 may determine whether the magnitude of the voltage ofthe second output electrode increases over the magnitude of thereference voltage Vref during the short detection period. If themagnitude of the voltage of the second output electrode increases overthe magnitude of the reference voltage Vref during the short detectionperiod, the power converter 10 may shut down to stop generating thepositive driving voltage ELVDD and the negative driving voltage ELVSS.If the magnitude of the voltage of the second output electrode is keptsmaller than the magnitude of the reference voltage Vref during theshort detection period, the power converter 10 may generate the otherone of the driving voltages ELVDD and ELVSS after the short detectionperiod, so that the power converter 10 may perform a normal operationafter the short detection period.

The short detection period may correspond to N frame cycles of thedisplay device 1000, where N is a positive integer. If a wiringconnected to the first output electrode and a wiring connected to thesecond output electrode are shorted with each other, the magnitude ofthe voltage of the second output electrode increases according to creaseof the magnitude of the selected one of the driving voltages ELVDD andELVSS. Therefore, as the length of the short detection period increases,the power converter 10 may be able to detect a more minute short betweenthe wiring connected to the first output electrode and the wiringconnected to the second output electrode, and thus stop generating thepositive driving voltage ELVDD and the negative driving voltage ELVSS.

In some example embodiments, the power converter 10 may provide thepositive driving voltage ELVDD at first and provide the negative drivingvoltage ELVSS after the short detection period. In this case, the powerconverter 10 may sense a voltage of an output electrode through whichthe negative driving voltage ELVSS is outputted to determine whether toshut down or not. The first driving voltage DV1 and the second drivingvoltage DV2 in the display device 1000 of FIG. 12 may correspond to thepositive driving voltage ELVDD and the negative driving voltage ELVSS,respectively.

In other example embodiments, the power converter 10 may provide thenegative driving voltage ELVSS at first and provide the positive drivingvoltage ELVDD after the short detection period. In this case, the powerconverter 10 may sense a voltage of an output electrode through whichthe positive driving voltage ELVDD is outputted to determine whether toshut down or not. The first driving voltage DV1 and the second drivingvoltage DV2 in the display device 1000 of FIG. 12 may correspond to thenegative driving voltage ELVSS and the positive driving voltage ELVDD,respectively.

The power converter 10 included in the display device 1000 of FIG. 13may have the same structure as the power converter 10 of FIG. 1. Astructure and an operation of the power converter 10 of FIG. 1 aredescribed above with reference to FIGS. 1 to 11. Thus, a detaileddescription of the power converter 10 included in the display device1000 of FIG. 13 will not be repeated.

FIG. 14 illustrates a circuit diagram of an example of a pixel includedin a display panel of a display device of FIG. 13. The display panel mayinclude a plurality of pixels.

Referring to FIG. 14, each of the plurality of pixels PX may include anorganic light emitting diode (OLED), a driving transistor Qd, aswitching transistor Qs, and a storage capacitor Cst.

The switching transistor Qs may be turned on in response to a gatesignal received through a gate line GL and provide the data signal DATAreceived through a data line DL to a first node NI. The storagecapacitor Cst may store the data signal DATA provided from the switchingtransistor Qs. The driving transistor Qd may be turned on in response toa voltage provided from the switching transistor Qs and/or the storagecapacitor Cst, and flow a driving current IDLED corresponding to amagnitude of the data signal DATA. The driving current IDLED may flowfrom the positive driving voltage ELVDD to the negative driving voltageELVSS through the driving transistor Qd and the organic light emittingdiode (OLED). An intensity of a light emitted from the organic lightemitting diode (OLED) may be determined by an intensity of the drivingcurrent IDLED.

The plurality of pixels PX may display an image in response to apositive driving voltage ELVDD, a negative driving voltage ELVSS, a gatesignal provided through the gate line GL, and a data signal DATAprovided through the data line DL. Thus, a wiring for the positivedriving voltage (ELVDD), a wiring for the negative driving voltage(ELVSS), the gate line GL, and the data line DL may be formed to overlapon the display panel 300. Therefore, the wiring for the positive drivingvoltage (ELVDD), the wiring for the negative driving voltage (ELVSS),the gate line GL, and the data line DL may be easily shorted with eachother by, e.g., a crack on the display panel and/or a foreign substancein the display panel 300.

As described above, the display device 1000 including the powerconverter 10 according to example embodiments may be able to detectminute short between wirings formed on the display panel 300 so that thedisplay device 1000 stops operating.

FIG. 15 illustrates a flow chart of an example of a method of driving adisplay device of FIG. 12.

Referring to FIG. 15, the power converter 10 may provide the firstdriving voltage DV1 at the first output electrode 110 to the displaypanel 300 (operation S100 in FIG. 15).

The power converter 10 may compare the magnitude of the voltage of thesecond output electrode 120 with the magnitude of the reference voltageVref during the short detection period (operation S200).

With respect to the comparison described above in connection withoperation S200, if the magnitude of the voltage of the second outputelectrode 120 is kept smaller than the magnitude of the referencevoltage Vref during the short detection period, the power converter 10may provide the second driving voltage DV2 at the second outputelectrode 120 after the short detection period, so that the displaydevice 1000 may perform a normal operation after the short detectionperiod (operation S300).

With farther respect to the comparison described above in connectionwith operation S200, if the magnitude of the voltage of the secondoutput electrode 120 equals to or increases over the magnitude of thereference voltage Vref during the short detection period, the powerconverter 10 may determine that the wirings formed on the display panel300 are shorted with each other and stop generating the first drivingvoltage DV1 and the second driving voltage DV2 (operation S400).

In some example embodiments, the first driving voltage DV1 may be thepositive driving voltage ELVDD having a positive potential and thesecond driving voltage DV2 may be the negative driving voltage ELVSShaving a negative potential.

In other example embodiments, the first driving voltage DV1 may be thenegative driving voltage ELVSS having a negative potential and thesecond driving voltage DV2 may be the positive driving voltage ELVDDhaving a positive potential.

FIG. 16 illustrates a flow chart of an example of a method of driving adisplay device of FIG. 12.

Referring to FIG. 16, a method of driving the display device. 1000according to FIG. 16 has the same steps as a method of driving thedisplay device 1000 according to FIG. 15, except that the powerconverter 10 may connect the second output electrode 120 to the groundvoltage GND through the pull-down resistor 231 during the shortdetection period (operation S150 in FIG. 16) before the power converter10 determines whether the magnitude of the voltage of the second outputelectrode 120 increases over the magnitude of the reference voltage Vrefduring the short detection period (operation S200).

If the power converter 10 does not connect the second output electrode120 to the ground voltage GND through the pull-down resistor 231 duringthe short detection period, the second output electrode 120 may befloated during the short detection period since the power converter 10outputs the first driving voltage DV1 at the first output electrode 110and does not outputs the second driving voltage DV2 at the second outputelectrode 120 during the short detection period. However, in the methodof driving the display device 1000 according to FIG. 16, since thesecond output electrode 120 is connected to the ground voltage GNDthrough the pull-down resistor 231 during the short detection period,the power converter 10 may more effectively determine whether themagnitude of the voltage of the second output electrode 120 increasesaccording to the increase of the magnitude of the first driving voltageDV1 during the short detection period.

The power converter 10 may separate the second output electrode 120 fromthe ground voltage GND after the short detection period since the powerconverter 10 performs a normal operation, in which the power converter10 simultaneously generates the first driving voltage DV1 at the firstoutput electrode 110 and the second driving voltage DV2 at the secondoutput electrode 120, after the short detection period.

FIG. 17 illustrates a flow chart of an example of a method of driving adisplay device of FIG. 12.

Referring to FIG. 17, a method of driving the display device 1000according to FIG. 17 has the same steps as a method of driving thedisplay device 1000 according to FIG. 16, except that the driving unit400 may provide the data signal DATA corresponding to black color to thedisplay panel 300 during the short detection period (operation S50 inFIG. 17) before the power converter 10 provides the first drivingvoltage DV1 at the first output electrode 110 to the display panel 300(operation S100).

As described with reference to FIGS. 13 and 14, the driving currentIOLED corresponding to a magnitude of the data signal DATA may flow fromthe positive driving voltage ELVDD to the negative driving voltage ELVSSthrough the driving transistor Qd and the organic light emitting diode(PLED). The intensity of the driving current IOLED may be a maximum whenthe data signal DATA corresponding to white color is provided to thedata line DL, and the intensity of the driving current IOLED may besubstantially zero when the data signal DATA corresponding to blackcolor is provided to the data line DL.

In the method of driving the display device 1000 according to FIG. 17,since the driving unit 400 provides the data signal DATA correspondingto black color to the display panel 300 during the short detectionperiod to prevent the driving current from flowing from the positivedriving voltage ELVDD to the negative driving voltage ELVSS, the powerconverter 10 may more effectively determine whether the magnitude of thevoltage of the second output electrode 120 increases according to theincrease of the magnitude of the first driving voltage DV1 during theshort detection period.

If the magnitude of the voltage of the second output electrode 120 iskept smaller than the magnitude of the reference voltage Vref during theshort detection period, the power converter 10 may start to generate thesecond driving voltage DV2 after the short detection period. Since ittakes some time for the power converter 10 to boost the second drivingvoltage DV2 to a target voltage level, the driving unit 400 may providethe data signal DATA corresponding to black color to the display panel300 for at least one frame cycle from the end of the short detectionperiod and then provide a valid data signal DATA to the display panel300.

In some example embodiments, the first driving voltage DV1 may be thepositive driving voltage ELVDD having a positive potential and thesecond driving voltage DV2 may be the negative driving voltage ELVSShaving a negative potential.

In other example embodiments, the first driving voltage DV1 may be thenegative driving voltage ELVSS having a negative potential and thesecond driving voltage DV2 may be the positive driving voltage ELVDDhaving a positive potential.

FIG. 18 illustrates a timing diagram for describing an opera of thedisplay device of FIG. 13.

FIG. 18 represents a timing diagram when the power converter 10 providesthe positive driving voltage ELVDD at first and provides the negativedriving voltage ELVSS after the short detection period, and the wiringsformed on the display panel 300 are not shorted with each other.

In FIG. 18, the short detection period Tsd corresponds to one framecycle of the display device 1000, and the driving unit 400 continuouslyprovides the data signal DATA corresponding to black color to thedisplay panel 300 during the short detection period Tsd and for oneframe cycle from the end of the short detection period Tsd, beforeproviding a valid data signal VALID DATA.

Hereinafter, an operation of the display device 1000 of FIG. 13 will bedescribed with reference to FIGS. 1 to 17.

The driving unit 400 may provide the first control signal EL_ON to thevoltage conversion unit 100 included in the power converter 10 insynchronization with the vertical synchronization signal Vsync while thedriving unit 400 provides the data signal corresponding to black colorBLACK DATA to the display panel 300. The voltage conversion unit 100 mayprovide the positive driving voltage ELVDD at the first output electrode110 by converting a power supply voltage VDD and enable the secondcontrol signal CON2 during the short detection period Tsd in response tothe first control signal EL_ON received from the driving unit 400. Sincethe wirings formed on the display panel 300 are not shorted with eachother, the voltage ELVSS of the second output electrode 120 does notincrease according to an increase of the positive driving voltage ELVDDand is kept at the ground voltage GND, which is smaller than themagnitude of the reference voltage Vref, during the short detectionperiod Tsd. Therefore, the short detection unit 200 included in thepower converter 10 disables the third control signal CON3 during theshort detection period Tsd. The voltage conversion unit 100 disables thesecond control signal CON2 and provides the negative driving voltageELVSS at the second output electrode 120 by converting the power supplyvoltage VDD after the short detection period Tsd, so that the powerconverter 10 performs a normal operation after the short detectionperiod Tsd.

FIG. 19 illustrates a timing diagram for describing an operation of thedisplay device of FIG. 13.

FIG. 19 represents a timing diagram when the power converter 10 providesthe positive driving voltage ELVDD at first and provides the negativedriving voltage ELVSS after the short detection period, and the wiringsformed on the display panel 300 are shorted with each other.

In FIG. 19, the short detection period Tsd corresponds to one framecycle of the display device 1000, and the driving unit 400 continuouslyprovides the data signal DATA corresponding to black color to thedisplay panel 300 during the short detection period Tsd and for oneframe cycle from the end of the short detection period Tsd, beforeproviding a valid data signal VALID DATA.

The driving unit 400 may provide the first control signal EL_ON to thevoltage conversion unit 100 included in the power converter 10 insynchronization with the vertical synchronization signal Vsync while thedriving unit 400 provides the data signal corresponding to black colorBLACK DATA to the display panel 300. The voltage conversion unit 100 mayprovide the positive driving voltage ELVDD at the first output electrode110 by converting a power supply voltage VDD and enable the secondcontrol signal CON2 during the short detection period Tsd response tothe first control signal EL_ON received from the driving unit 400. Sincethe wirings formed on the display panel 300 are shorted with each other,the voltage ELVSS of the second output electrode 120 increases accordingto the increase a the positive driving voltage ELVDD during the shortdetection period Tsd. When the magnitude of the voltage ELVSS of thesecond output electrode 120 increases over the magnitude of thereference voltage Vref during the short detection period Tsd, the shortdetection unit 200 included in the power converter 10 enables the thirdcontrol signal CON3. As illustrated in FIG. 19, when the third controlsignal CON3 is enabled, the voltage conversion unit 100 stops generatingthe positive driving voltage ELVDD and a magnitude of the positivedriving voltage ELVDD decreases to the ground voltage GND. According tothe decrease of the positive driving voltage ELVDD, the voltage ELVSS ofthe second output electrode 120 also decreases to the ground voltageGND, so that the power converter 10 shuts down.

FIG. 20 illustrates a timing diagram for describing an operation of thedisplay device of FIG. 13.

FIG. 20 represents a timing diagram when the power converter 10 providesthe negative driving voltage ELVSS at first and provides the positivedriving voltage ELVDD after the short detection period, and the wiringsformed on the display panel 300 are not shorted with each other.

In FIG. 20, the short detection period Tsd corresponds to one framecycle of the display device 1000, and the driving unit 400 continuouslyprovides the data signal DATA corresponding to black color to thedisplay panel 300 during the short detection period Tsd and for oneframe cycle from the end of the short detection period Tsd, beforeproviding a valid data signal VALID DATA.

The driving unit 400 may provide the first control signal EL_ON to thevoltage conversion unit 100 included in the power converter 10 insynchronization with the vertical synchronization signal Vsync while thedriving unit 400 provides the data signal corresponding to black colorBLACK DATA to the display panel 300. The voltage conversion unit 100 mayprovide the negative driving voltage ELVSS at the first output electrode110 by converting a power supply voltage VDD and enable the secondcontrol signal CON2 during the short detection period Tsd in response tothe first control signal EL_ON received from the driving unit 400. Sincethe wirings formed on the display panel 300 are not shorted with eachother, the voltage ELVDD of the second output electrode 120 does notdecrease according to a decrease of the negative driving voltage ELVSSand is kept at the ground voltage GND, which is smaller than themagnitude of the reference voltage Vref, during the short detectionperiod Tsd. Therefore, the short detection unit 200 included in thepower converter 10 disables the third control signal CON3 during theshort detection period Tsd. The voltage conversion unit 100 disables thesecond control signal CON2 and provides the positive driving voltageELVDD at the second output electrode 120 by converting the power supplyvoltage VDD after the short detection period Tsd, so that the powerconverter 10 performs a normal operation after the short detectionperiod Tsd.

FIG. 21 illustrates a timing diagram for describing an operation of thedisplay device of FIG. 13.

FIG. 21 represents a timing diagram when the power converter 10 providesthe negative driving voltage ELVSS at first and provides the positivedriving voltage ELVDD after the short detection period, and the wiringsformed on the display panel 300 are shorted with each other.

In FIG. 21, the short detection period Tsd corresponds to one framecycle of the display device 1000, and the driving unit 400 continuouslyprovides the data signal DATA corresponding to black color to thedisplay panel 300 during the short detection period Tsd and for oneframe cycle from the end of the short detection period Tsd, beforeproviding a valid data signal VALID DATA.

The driving unit 400 may provide the first control signal EL_ON to thevoltage conversion unit 100 included in the power converter 10 insynchronization with the vertical synchronization signal Vsync while thedriving unit 400 provides the data signal corresponding to black colorBLACK DATA to the display panel 300. The voltage conversion unit 100 mayprovide the negative driving voltage ELVSS at the first output electrode110 by converting a power supply voltage VDD and enable the secondcontrol signal CON2 during the short detection period Tsd in response tothe first control signal EL_ON received from the driving unit 400. Sincethe wirings formed on the display panel 300 are shorted with each other,the voltage ELVDD of the second output electrode 120 decreases accordingto the decrease (Ante negative driving voltage ELVSS during the shortdetection period Tsd. When the magnitude of the voltage ELVDD of thesecond output electrode 120 increases over the magnitude of thereference voltage Vref during the short detection period Tsd, the shortdetection unit 200 included in the power converter 10 enables the thirdcontrol signal CON3. As illustrated in FIG. 21, when the third controlsignal CON3 is enabled, the voltage conversion unit 100 stops generatingthe negative driving voltage ELVSS and a magnitude of the negativedriving voltage ELVSS decreases to the ground voltage GND. According tothe decrease of the magnitude of the negative driving voltage ELVSS, themagnitude of the voltage ELVDD of the second output electrode 120 alsodecreases to the ground voltage GND, so that the power converter 10shuts down.

As described above, the power converter 10 may provide the first drivingvoltage DV1 at the first output electrode 110 and the second drivingvoltage DV2 at the second output electrode 120 at a time interval of theshort detection period while the driving unit 400 provides the datasignal DATA corresponding to black color to the display panel 300. Thepower converter 10 may determine whether the magnitude of the voltage ofthe second output electrode 120 increases according to an increase ofthe magnitude of the first driving voltage DV1 during the shortdetection period. If the magnitude of the voltage of the second outputelectrode 120 increases over the magnitude of the reference voltage Vrefduring the short detection period, the power converter 10 may determinethat the wirings formed on the display panel 300 are shorted with eachother and stop generating the first driving voltage DV1 and the seconddriving voltage DV2. Therefore, the power converter 10 may detect aminute short between the wirings formed on the display panel 300effectively.

FIG. 22 illustrates a block diagram of a system including a displaydevice according to example embodiments.

In the example embodiment shown in FIG. 22, a system 6000 includes thedisplay device 1000, a processor 2000, a storage device 3000, a memorydevice 4000, and an I/O device 5000. The display device 1000 may includethe display panel 300, the power converter 10, and the driving unit 400.

The storage device 3000 may store image data. The storage device 3000may include a solid state drive (SSD) a hard disk drive (HDD), a CD-ROM,etc.

The display device 1000 may display the image data stored in the storagedevice 3000.

The display panel 300 may include a plurality of pixels, each of whichoperates in response to the first driving voltage DV1, the seconddriving voltage DV2, and the data signal DATA.

The power converter 10 may provide the first driving voltage DV1 at afirst output electrode of the power converter 10 and the second drivingvoltage DV2 at a second output electrode of the power converter 10 at atime interval of a short detection period in response to a first controlsignal CON1. The power converter 10 may shut down to stop generating thefirst driving voltage DV1 and the second driving voltage DV2 when amagnitude of a voltage of the second output electrode is equal to orlarger than a magnitude of a reference voltage during the shortdetection period.

The driving unit 400 may provide the data signal DATA to the displaypanel 300 and provide the first control signal CON1 to the powerconverter 10.

The display device 1000 may be implemented using various kinds of adisplay panel in so far as the display panel 300 displays an image usingat least two driving voltages DV1 and DV2 received from the powerconverter 10. For example, the display device 1000 may include anorganic light emitting display device. In this case, each of theplurality of pixels included in the display panel 300 includes anorganic light, emitting diode (OLED).

The display device 1000 may have the same structure as the displaydevice 1000 of FIG. 12. A structure and an operation of the displaydevice 1000 of FIG. 12 are described above with reference to FIGS. 1 to21. Thus, a detailed description of the display device 1000 included inthe system 6000 will not be repeated.

The processor 2000 may control the storage device 3000 and the displaydevice 1000. The processor 2000 may perform specific calculations,computing functions for various tasks, etc. The processor 2000 mayinclude, e.g., a microprocessor or central processing unit (CPU). Theprocessor 2000 may be coupled to the storage device 3000 and the displaydevice 1000 via an address bus, a control bus, and/or a data bus. Inaddition, the processor 2000 may be coupled to an extended bus such as aperipheral component interconnection (PCI) bus.

As discussed above, the system may include the memory device 4000 andthe I/O device 5000. In some example embodiments, the system 6000 mayfurther include a plurality of ports (not illustrated) that communicatewith a video card, a sound card, a memory card, a universal serial bus(USB) device, other electric devices, etc.

The memory device 4000 may store data for operations of the system 6000.For example, the memory device 4000 may include at least on memorydevice such as a dynamic random recess memory (DRAM) device, a staticrandom access memory (SRAM) device, etc., and/or at least onenon-volatile memory device such as art erasable programmable read-onlymemory (EPROM) device, electrically erasable programmable read-onlymemory (EEPROM) device, a flash memory device, etc.

The I/O device 5000 may include one or more input devices (e.g., akeyboard, keypad, a mouse, a touch pad, a haptic device, etc.), and/orone or more output devices (e.g., a printer, a speaker, etc.). In someexample embodiments, the display device 1000 may be included in the I/Odevice 5000.

The system 6000 may include any of several types of electronic devises,such as a digital television, a cellular phone, a smart phone, apersonal digital assistant (PDA), a personal media player (PMP), aportable game console, a computer monitor, a digital camera, an MP3player, etc.

A wiring for the positive driving voltage (ELVDD) and a wiring for thenegative driving voltage (ELVSS) may be formed so that they overlap onthe display panel. If the wiring for the positive driving voltage(ELVDD) and the wiring tear the negative driving voltage (ELVSS) areshorted with each other by, for example, a crack on the display paneland/or a foreign substance in the display panel, heating problem and/ora tire may be caused because of an overcurrent at the short circuit ifthe short circuit is left unchecked. In this regard, as described above,the power converter and the display device including the power converteraccording to the example embodiments may be able to effectively detect aminute short between wirings formed on the display panel, and shut downif needed. Example embodiments may thus provide a power converter thatdetects a minute short between output electrodes effectively.

As described above, example embodiments relate to a display deviceincluding the power converter, a system including the display device,and a method of driving the display device.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of skill in the art as of thefiling of the present application, features, characteristics, and/orelements described in connection with a particular embodiment may beused singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A display device, comprising: a display panelincluding a plurality of pixels, the pixels being configured to operatein response to a first driving voltage, a second driving voltage, and adata signal; a voltage converter that provides the first driving voltageand the second driving voltage to the display panel, the voltageconverter including a first output, which outputs the first drivingvoltage to first wiring of the display panel, and a second output, whichoutputs the second driving voltage to second wiring of the displaypanel, the voltage converter selectively starting an output of thesecond driving voltage after a detection period, the detection periodbeing after the output of the first driving voltage; and a comparatorconfigured to control the output of the first and second drivingvoltages of the voltage converter based on a magnitude of a wiringvoltage corresponding to voltage on the second wiring.
 2. The displaydevice as claimed in claim 1, wherein the comparator includes: a firstinput that receives the wiring voltage corresponding to the voltage onthe second wiring; a second input that receives a reference voltage; andan output that outputs a comparison signal to the voltage converter. 3.The display device as claimed in claim 2, wherein, at the end of thedetection period, the voltage converter evaluates the comparison signaland selectively starts the output of the second driving voltagedepending on the evaluation of the comparison signal.
 4. The displaydevice as claimed in claim 3, wherein comparator selectively outputs thecomparison signal with a first level or a second level depending on therelative magnitudes of the wiring voltage and the reference voltage, andthe voltage converter starts the output of the second driving voltage ifthe comparison signal has the first level when evaluated by the voltageconverter.
 5. The display device as claimed in claim 4, wherein thevoltage converter shuts down output of the first driving voltage if thecomparison signal has the second level when evaluated by the voltageconverter.
 6. The display device as claimed in claim 2, wherein thecomparison signal has the second level if the voltage at the firstinput, which receives the wiring voltage, is between the referencevoltage and the first driving voltage.
 7. The display device as claimedin claim 2, wherein the voltage converter stops providing the firstdriving voltage and the second driving voltage in response to a state ofthe comparison signal.